<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2017/9/20
 * Time: 14:50
 */
header("Content-type:text/html;charset=utf-8");
$s = '我在学习习习PHP';
$len = mb_strlen($s,"utf-8");
var_dump($len);

$firstChar = mb_substr($s,1,2,'UTF8');
var_dump($firstChar);
//mb_stripos()
//mb_strripos()
//mb_strstr()
//mb_strrichr()
// mb_strrchr()